Add JSON.pm to third_party

third_party/JSON/JSON-2.59/t/e13_overloaded_eq.t

+#!/usr/bin/perl
+
+use strict;
+use Test::More tests => 4;
+
+BEGIN {
+    $ENV{ PERL_JSON_BACKEND } = "JSON::backportPP";
+}
+
+use JSON;
+
+my $json = JSON->new->convert_blessed;
+
+my $obj = OverloadedObject->new( 'foo' );
+ok( $obj eq 'foo' );
+is( $json->encode( [ $obj ] ), q{["foo"]} );
+
+# rt.cpan.org #64783
+my $foo  = bless {}, 'Foo';
+my $bar  = bless {}, 'Bar';
+
+eval q{ $json->encode( $foo ) };
+ok($@);
+eval q{ $json->encode( $bar ) };
+ok(!$@);
+
+
+package Foo;
+
+use strict;
+use overload (
+    'eq' => sub { 0 },
+    '""' => sub { $_[0] },
+    fallback => 1,
+);
+
+sub TO_JSON {
+    return $_[0];
+}
+
+package Bar;
+
+use strict;
+use overload (
+    'eq' => sub { 0 },
+    '""' => sub { $_[0] },
+    fallback => 1,
+);
+
+sub TO_JSON {
+    return overload::StrVal($_[0]);
+}
+
+
+package OverloadedObject;
+
+use overload 'eq' => sub { $_[0]->{v} eq $_[1] }, '""' => sub { $_[0]->{v} }, fallback => 1;
+
+
+sub new {
+    bless { v => $_[1] }, $_[0];
+}
+
+
+sub TO_JSON { "$_[0]"; }
+